1. Technical Field
The present invention relates to an image forming apparatus having tab sheet inserting function, a computer readable recording medium stored with a control program for controlling the image forming apparatus, and its control method.
2. Description of the Related Art
There exist printing apparatuses such as copying machines and printers that are capable of creating printed products by inserting between pages a tab sheet having a flat rectangular main body and a tab protruding at a specified position on a side of said main body. See Japanese Unexamined Patent Publication No. 2005-271259.
In such a printing apparatus, multiple sets of tab sheets consisting of, for example, five tab sheets, whose tab positions are sequentially offset from each other, are used as constituents and are placed in a sheet supply tray. If only first three tab sheets are used in a printing job, the remaining two tab sheets, i.e., the fourth and fifth tab sheets, become no longer necessary and must be discharged. This is because it is necessary to supply tab sheets starting with the first tab sheet of a set in the execution of the next print job.
In the meanwhile, those tab sheets that became no longer necessary can be reused after being discharged. However, as shown in the example described above, the tab sheets that are discharged as unnecessary ones are mostly those with their tabs located in lower positions such as the fourth and fifth. Consequently, this causes a problem of shortage of those tab sheets that belong in the first half of a set, e.g., the first and second sheets, making the system inconvenient to use.